Method of making grooved wire



D. B. FULMER El AL METHOD OF MAKING GROOVED WIRE Filed Nov. 25, 1933 2Sheets-Sheet 1 gwueniod Q 5 Dana 15. Fzqlzner March 31, 1936.

ww k r Md N MWMN March 31, 1936. D, ME ET AL 2,036,034

METHOD OF MAKING GROQVED WIRE Filed Nov. 25, 1933 2 Sheets-Sheet 2fioIzaldR Mr Patented Mar. 31, 1936 METHOD OF MAKING GROOVED WIRE DonaldB. Fulmer, Bethlehem, and William T.

Miller, Lehigh County, Pa., assignors to Bethlehem Steel Company, acorporation of Pennsylvania Application November 25, 1933, Serial No.699,654

' 17 Claims. (Cl. 29-148) This invention relates to an improved methodof making wire having a continuous longitudinal roove or flute formed inits surface, and the article produced thereby.

Wire of this character is extensively used in the manufacture of bedsprings, to form the outer edges of the assembled spring and at the simetime to provide a means for securing the outer coils of the spring tothe edge or binding wire by crimping the wire over a portion of thecoils.

Heretofore wire of this character was produced by taking a plain, colddrawn steel wire and machining a continuous groove in its surface, ormachining a series of spaced grooves along its length. These methods,however, proved to be a slow and expensive way of producing wire of thisnature.

We have devised a method. of forming wire of this character in a rollingmill, which may be used directly as a commercial article, or if a highergrade wire is desired we take the finished rolled product of the mill,or a rolled shape partly of the final section and subject it to a coldworking operation of its entire surface, including the groove, whichproduces a stifier and more finely finished wire of greater accuracythan the hot rolled product, or that produced by former methods.

The novel features of our invention will be more fully understood fromthe following description and claims taken with the drawings, in which:

Fig. 1 shows a series of rolling mill passes for producing a groovedround.

I for cold drawing wire.

Fig.5 is an end view of the drawing die used on the draw bench.

Fig. 6 shows a longitudinal section of the die.

Fig. '7 diagrammatically represents a bending, straightening andshearing machine.

Fig. 8 shows a partial section of two rolls used in the machineillustrated in Fig. 7, and;

Fig. 9 shows an arrangement of rolls for cold working and shaping thewire to finished size.

Referring to Fig. 1, to roll a grooved wire we start with a heated steelsquare l which is reduced to an oval ll then to a diamond l2; then to afluted square I3 which is passed between plain faced rolls to form arectangular section M. The rectangular section is then turned on end andentered into a leader pass of section IS. The

top roll of this pass has an annular V shaped portion which projectsinto the channeled portion of the bottom roll so as to form asubstantally trapeziform section with a V shaped groove in its broaderparallel face. The leader is then entered into pass Hi to form what weterm a fluted round, and from that pass the piece may be coiled forsubsequent cold working operations or else it may be entered while hotinto a final closing pass I! to transform the V shaped groove to Ushape. This last pass I! may be provided with a horn or a rotatablemandrel l8 upon which the fluted round is closed, so as to provide agauge for limiting the closing in of the portions of the round formingthe U shaped groove. This pass also trues up the shape generally.

Fig. 2 shows more in detail the shape of the coacting rolls for formingthe leader. The bottom roll I9 is machined to form an annular channelhaving side walls 20 converging from its face 2| toward the axis of theroll, while the top roll 22 has a V shaped annular portion 23 projectingoutwardly from its face 24, the apex 25 of the projection being rounded.It will be noted that when the two rolls are aperatively aligned thatthere are open spaces 26".l'3etween the rolls to allow the metal of thesection forming the leader to flow upwardly after the lower cavity ofthe pass has been'filled. The section thus formed is substantiallytrapeziform with a V shaped groove in its broader parallel face 21.narrow parallel face 29 are rounded. It will also be noted that theleader section is partly of the shape of the fluted round, inasmuch thatthe groove of the finished section is partially formed before enteringthe finishing pass i6. When the leader properly proportioned and shapedsuch as we have shown, is entered into the round finish-' in pass ofFig. 3, a grooved round can be rolled without finning at the parting ofthe rolls.

In the finishing pass as shown in Fig. 3 the bottom roll is made with arounded annular groove 30 struck from a point 3| outside the face 21 ofthe roll. The top roll is likewise grooved from its outer face '24 topoints 32. These grooves being struck from the point 33 which is belowthe point 31' of the radius for the bottom roll. With these radii pointsoffset and the radius 33' being slightly larger than radius 34, aneccentric pass is produced. From points 32 a V-shaped annular section 35is formed on the top roll with the point truncated and rounded as at 36.Thus by proper alignment of the rolls a rounded pass is formed whichwill produce a rolled section having a V shaped groove extend- Thecorners 28 at the ing longitudinally its length. It will be noted thatthe annular section 35 of the finishing pass is of less angularity thanthe groove of the leader and that the round point 36 is of larger radiusthan the groove in the leader so that when the leader enters thefinishing pass it is pressed and deformed by the rolls so as to fill outthe upstanding openings of the pass in the top roll and fill up therounded portion of the bottom roll. The side walls 20 of the leader willbe bulged outwardly only sufficiently to fill the pass without flnningat the parting of the rolls. A leader of this shape is easily enteredinto the finishing pass because it has a preformed groove which isengaged by the top roll of the finishing pass and at the same time it isproperly centered in the pass, whereby an equal distribution or fillingout of the pass is effected without firming.

After the rolling operation the coiled material is pickled or otherwisesuitably treated to remove the scale and then lime dipped in a usualmanner preparatory to the cold working operation.

For cold drawing we prefer to take the rolled rod as it comes from passl6 and draw it through a die as shown in Figs. 5 and 6 so as to slightlyreduce its sectional area and at the same time transform the V shapedgroove of the rod to u shape. This operation ,not only produces a brightand accurately finished wire but at the same time adds greatly to itsstiffness which is much desired when used as binding or frame members ofbed springs.

The drawing die is made in two parts, the die body 31, and the grooveforming tongue 38. The tongue is replaceable and may be made frommaterial different from the die body 31. The opening 39 at the enteringend of the die is flared so as to receive the rod which is slightlylarger in section than the reducing orifice 39 in the body of the die.Screws 40 are provided for holding the tongue 38 in place. The die ismounted in a die block 4| which is attached to the draw table 42. Thedrawing drum 43, reel 44 and lubricating box 45 are of the usualconstruction.

As the section formed in pass 16 is drawn through the die, theupstanding side portions or fingers of the rod are bent toward eachother into contact with the tongue 38 of the die which changes the Vshaped groove of the rod to U shape and at the same time reduces thecross section of the rod to a substantially round wire section, whichpreviously to drawing was only partly of the finished section or anapproximate round, the tongue serving as a gauge for limiting theclosing in of finger portions of the rolled section and for drawing aclean cut' and accurate groove. We may, however, take the rod as shapedin pass I! of the hot mill and give it a skin drawing pass to slightlyreduce its section so as to obtain a brightly finished and stiffer wireby drawing it through a die similar to the one we have illustrated.Again, we may take the fluted round l6 having a V shaped groove anddeform the rod when cold to provide a groove of U shape by means ofrolls as shown in Fig. 9. This in a measure would be equivalent to acold drawing operation.

From experience it has been found that when a wire of this particularsection has been drawn through a die so as to reduce its section andeffect a general deformation of the physical structure of the material,that certain stresses are set up in the wire which tend to twist itabout its axis after the drawing tension has been released. Thesestresses also impart to the drawn wire a bowed or wavy effect. Theseconditions may be due to the fact that the wire is unsymmetrical insection, unlike a solid round. As a result of the drawing operation thewire is unfit for immediate use because the groove in the wire does notrun in a straight line, which is essential for its intended purpose. Tocorrect this misalignment of the groove in the wire and to effect ageneral straightening of the wire, we run it through a straighteningmachine of the character shown in Patent 1,751,094, generally called. aShuster straightener, the principal features being shown diagrammaticalyin Fig. 7.

While a straightener of this type will effectively straighten a piece,it does not provide any means for correcting for axial twist so as toposition the groove in the wire in a straight line. To accomplish thiswe substitute special rolls 46 and 41 as shown in Fig. 8 for theordinary, adjustable straightening rolls commonly known in the art asbreakers. The feed rolls 52 and 55 may also be shaped after this mannerif desired. The upper rolls 46 are each provided with a roundedperipheral groove 48 and an annular tongue portion 49 extendingoutwardly from the base of the groove which is adapted to engage thegroove of the wire. These upper rolls are provided with suitable meansfor positioning them relatively to the bottom rolls 4"! so as to flexthe wire passing therebetween. The lower rolls are positively driven,the upper rolls rotating freely to respond to conditions as they may beimposed.

When starting a coil of wire through the straightener, the advancing endof the wire is threaded through the rolls so that the groove in the wireregisters with the tongues of the top rolls. To do this it may benecessary to twist the end of the wire so as to effect this alignment,due to its inherent twist. With the groove thus properly aligned andheld in position, the flexing action of the breakers" simultaneouslyrelieves the stresses in wire which originally caused it to twist,thereby correcting for this misalignment. In other words the rolls 46actually twist the wire about its axis at the same time the stresseswhich caused the initial twist are being relieved, so as to effectivelycorrect for the initial twist. After the wire has been corrected fortwist, it passes on to the fiier straightening unit 5|, then to the feedrolls 52, after which it is automatically cut into fixed lengths bymeans of shears 53. The gauge 54 at the end of the machine determinesthe length of the piece to be cut and automatically controls the actionof the shears. The straightened rods with properly aligned grooves arethen bundled for shipment.

It will be apparent that a grooved wire produced after this manner willhave superior qualities to a drawn wire having a machined groove.because by this new method the entire surface of the wire, including thegroove, is cold worked so as to produce a uniform grain structure aroundits entire enveloping surface, thus increasing its stiffness which is animportant feature when used as a binding or frame member. Where a grooveis machined in a cold drawn wire, the continuity of the drawn skin ofthe wire is broken and the material defining the groove is not of thesame grain structure as the outside surface of the wire, therebyimpairing its stiffness.

Having thus described our invention, what we claim as new and desire tosecure by Letters Patent is:

(ill

1. The method of producing wire having a continuous longitudinal groovein its surface, com- .prising rolling a, grooved rod of larger section ias to reduce'its section, and then axially twisting and flexing the wirethus formed and simultaneously straightening the same so as to positionthe groove in the wire in a straight line.

3. The method of producing wire having a continuous longitudinal groovein its surface, comprising rolling a grooved rod of larger sectionthan'the finished size, cold drawing said rod so ,as to reduce andstiffen its section, then relievprising rolling a rod of larger sectionthan the finished size with a V shaped groove therein, cold drawing saidrod so as to reduce its section and simultaneously deformingthe materialdefining the V shaped groove so as to form a groove of U shape, thenrelieving the drawing stresses tending to twist the wire by ,a flexingoperation while correcting for twist, and further straightening the wireso as to position the groove in the wire in a straight line.

5. The method of producing wire having a vcontinuous longitudinal groovein its surface, comprising rolling a rod partly of the finished sectionwith a continuous longitudinal V shaped groove therein, reducing saidrod by ,a cold working operation to the finished wire size and at thesame time shaping said V shaped groove to U shape, and then by anothercold working operation correcting for any existing axial twist in thewire and simultaneously straightening same longitudinally its axis.

6. The method of producing wire having a continuous longitudinal groovein its surface, comprising producing an approximately round hot rolledrod having a longitudinal V shaped groove with a rounded bottom in itssurface, closing in on the portions of the rod defining said V groove soas to form a U shaped groove, and then correcting for transverse angularmisalignment of said groove and straightening the piece in a singleoperation.

'7. The method of producing wire having a straight longitudinal groovein its surface, comprising forming in a rolling mill pass, an elongatedleader of trapeziform cross section with a V shaped recess in itsbroader parallel face, reducing said leader in another roll pass to afluted round, deforming said fluted round to a round of the finishedsize having a U shaped groove in its surface by a cold workingoperation, and by another cold working operation relieving the anelongated leader of trapeziform cross section with a V shaped recess inits broader parallel face, reducing said leader in another roll pass toa fluted round section, coiling said rod as it emerges from the lastroll pass, suitably preparing the coiled rod for a cold drawingoperation, then drawing the rod through a die to further reduce itssection to a round wire and to transform said v shaped groove to one ofU shape and again coiling the wire, then feeding the coiled wire into astraightening device adapted to engage the groove and the surfaceopposite the groove at a plurality of points in staggered relation alongthe wire so as to flex the same, whereby' the torsional drawing stressesare relieved and said groove is positioned in a common plane, andcutting the straightened wire to desired lengths.

9. The method of producing wire having a straight longitudinal groove inits surface, the steps comprising forming in a rolling mill pass, anelongated leader of trapeziform cross section with a V shaped recess inits broader parallel face, reducing said leader in another'roll pass toa fluted round section, coiling said rod as it emerges from the lastroll pass, preparing the coiled rod,

for a cold drawing operation, then drawing the rod through a die tofurther reduce its section to a round wire and to transform said Vshaped groove to, one of U shape and again coiling the Wire, thenengaging the grooved-portion of the wire so as to efiect its axialrotation and simultaneously flexing the material, whereby to remove thebend due to its coiled condition and to correct for axial twist in thewire, and cutting the wire to desired lengths.

10. The method of rolling round wire having a longitudinal groove in itssurface, comprising forming in a roll pass an elongated heated leader oftrapeziform cross section having a V shaped groove in its wide parallelface, passing said leader through another roll pass formed to reduce itssection to an approximate round having a V shaped groove in its surface,and in another pass partly closing said V shaped groove to U shape androunding up the section.

11. The method of rolling round wire having a longitudinal groove in itssurface, comprising forming in a roll pass an elongated heated leader oftrapeziform cross section having a V shaped groove in its wide parallelface, passing said leader through another roll pass formed to reduce itssection to an approximate round having a V shaped groove with a roundedbottom in its surface, and in a cold rolling operation partly closingsaid V shaped groove to U shape and sizing up the section.

12. The method of rolling round wirehaving a longitudinal groove in itssurface, comprising forming in a roll pass a leader of trapeziformsection having a groove extending longitudinally its length in its wideparallel face passing said leader through another roll pass formed to anapproximate round with a V shaped portion on one of the rolls extendinginto the pass so as to produce a fluted round, and in another suitablepass partly closing the fluted portion of said round to form a roundhaving U shaped groove in its surface.

13. The method of producing round wire having a longitudinal groove inits surface, comprising forming in a'roll pass a heated leader of tra- Ppeziform section having a groove extending longitudinally its wideparallel face, passing said leader through another roll pass formed toreduce its section to an approximate round having a groove converginginwardly toward its axis, and

continuously passing said round through another roll pass formed toconvert said converging groove to U shape and round up the section, thenin another operation giving the finished rolled wire a light colddrawing pass to accurately size and reduce its sectional area.

14. The method of producing wire having a continuous U shaped groove inits surface, comprising producing an approximately round bar having acurved bottom and curved side portions struck from different points on avertical line passing through its axis and a depressed V shaped groovein its top portion extending approximately to its axis, and in anotheroperation deforming said side portions so as to transform said V shapedgroove to U shape.

15. The method of rolling a round section having a longitudinal groovein its surface, comprising forming in a roll pass an elongated leader ofgreater section than the finished round and having a flat bottomportion, upwardly and outwardly extending side faces and a downwardlyextending angular groove in its upper face, then entering said leaderinto a finishing roll pass of rounded section having an inwardlyextending angularly shaped portion of less angularity than the groove ofsaid leader for compressing said leader in the direction of its depth tolaterally spread the middle portion of said side faces while closing inon their upper portions to round same and narrow said groove,and'simultaneously deform said flat bottom portion whereby to fill outthe rounded pass without finnlng.

16. The method of rolling a round section having a longitudinal groovein its surface, comprising deforming a bar having a major and a minoraxis in an open roll pass to form a leader having a narrow bottomportion and a wider top portion with a groove therein withoutrestricting the flow of material in the direction of its top portion,then entering said leader into a finishing pass of rounded sectionhaving an inwardly extending angularly shaped portion to compress theleader in the direction of its major axis whereby to narrow said widetop portion while spreading that portion intermediate its top and bottomportions so as to fill out the pass without finning.

1'7. The method of rolling a round section having a longitudinal groovein its surface, comprising compressing in an open roll pass a heated barof rectangular section in the direction of its major axis to form aleader having a narrow bottom portion and a top portion wider than saidbar with a groove therein without restricting the flow of material inthe direction of the groove, then compressing said leader in a roundedroll pass having an inwardly extending angularly shaped portion so as toreduce the leader in the direction of the groove whereby to spread theleader and fill out the rounded pass without flnning.

DONALD B. FULMER. WILLIAM T. MILLER.

